QGraphicsWidget update issues with ItemHasNoContents + effect

Items with the ItemHasNoContents flag set are never drawn so the
'paintedViewBoundingRect' is never cached/updated resulting in
updates wrongly being discarded. The solution is to always invalidate
the children for such items.

Auto test included.

Task-number: QT-3803

2 files changed, 32 insertions, 2 deletions

diff --git a/src/gui/graphicsview/qgraphicsscene.cpp b/src/gui/graphicsview/qgraphicsscene.cpp
index 36a24db..921e121 100644
--- a/src/gui/graphicsview/qgraphicsscene.cpp
+++ b/src/gui/graphicsview/qgraphicsscene.cpp
@@ -4984,14 +4984,15 @@ void QGraphicsScenePrivate::markDirty(QGraphicsItem *item, const QRectF &rect, b
         return;
     }
 
-    bool hasNoContents = item->d_ptr->flags & QGraphicsItem::ItemHasNoContents
-                         && !item->d_ptr->graphicsEffect;
+    bool hasNoContents = item->d_ptr->flags & QGraphicsItem::ItemHasNoContents;
     if (!hasNoContents) {
         item->d_ptr->dirty = 1;
         if (fullItemUpdate)
             item->d_ptr->fullUpdatePending = 1;
         else if (!item->d_ptr->fullUpdatePending)
             item->d_ptr->needsRepaint |= rect;
+    } else if (item->d_ptr->graphicsEffect) {
+        invalidateChildren = true;
     }
 
     if (invalidateChildren) {
diff --git a/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp b/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp
index fa6a5ec..e1bfb79 100644
--- a/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp
+++ b/tests/auto/qgraphicseffect/tst_qgraphicseffect.cpp
@@ -76,6 +76,7 @@ private slots:
     void dropShadowClipping();
     void childrenVisibilityShouldInvalidateCache();
     void prepareGeometryChangeInvalidateCache();
+    void itemHasNoContents();
 };
 
 void tst_QGraphicsEffect::initTestCase()
@@ -675,6 +676,34 @@ void tst_QGraphicsEffect::prepareGeometryChangeInvalidateCache()
     QCOMPARE(item->nbPaint, 0);
 }
 
+void tst_QGraphicsEffect::itemHasNoContents()
+{
+    QGraphicsRectItem *parent = new QGraphicsRectItem;
+    parent->setFlag(QGraphicsItem::ItemHasNoContents);
+
+    MyGraphicsItem *child = new MyGraphicsItem;
+    child->setParentItem(parent);
+    child->resize(200, 200);
+
+    QGraphicsScene scene;
+    scene.addItem(parent);
+
+    QGraphicsView view(&scene);
+    view.show();
+    QTest::qWaitForWindowShown(&view);
+    QTRY_COMPARE(child->nbPaint, 1);
+
+    CustomEffect *effect = new CustomEffect;
+    parent->setGraphicsEffect(effect);
+    QTRY_COMPARE(effect->numRepaints, 1);
+
+    for (int i = 0; i < 3; ++i) {
+        effect->reset();
+        effect->update();
+        QTRY_COMPARE(effect->numRepaints, 1);
+    }
+}
+
 QTEST_MAIN(tst_QGraphicsEffect)
 #include "tst_qgraphicseffect.moc"